A transparent and bendable nanofiber pressure sensor could lead to significant improvements in implantable and wearable devices.

Conventional pressure sensors cannot make accurate measurements if they are twisted or wrinkled and are difficult to scale down to less than 100 micrometers in thickness.

Motivated to expand pressure sensor use, an international team of researchers developed a sensor capable of measuring the pressure distribution of rounded surfaces. The complete pressure sensor incorporates organic transistors and electronic switches made from carbon- and oxygen-based organic materials into a pressure sensitive nanofiber structure.

At approximately eight micrometers thick and capable of bending over a radius of 80 micrometers, the sensor can make measurements in 144 locations simultaneously.

Nanofiber Gloves?

By combining carbon nanotubes, graphene and an elastic polymer, the flexible nanofiber could create the first pressure-sensing glove to test for breast tumors. Instead of squishing breasts in mammograms or taking a piece of tissue through biopsies, the glove would offer patients a less invasive option.

The flexible pressure sensor conforms to the shape of an inflated balloon. Even when the sensor is stretched and deformed with the shape of the balloon, the device still measures the pressure distribution accurately. (Image courtesy of Someya Laboratory.)

"We've also tested the performance of our pressure sensor with an artificial blood vessel and found that it could detect small pressure changes and speed of pressure propagation," said Sungwon Lee of the University of Tokyo’s graduate school of engineering.

"Flexible electronics have great potential for implantable and wearable devices. I realized that many groups are developing flexible sensors that can measure pressure but none of them are suitable for measuring real objects since they are sensitive to distortion. That was my main motivation and I think we have proposed an effective solution to this problem,” Lee concluded.